Acer palmatum Thunb.

Welcome to Tips Tree Planting! Today, we’re going to dive into the enchanting world of Acer palmatum Thunb., also known as the Smooth Japanese Maple. As a lover of gardening and someone with years of experience, I can assure you that this deciduous tree is a true gem in any garden.

The Beauty of Acer Palmatum

With its rounded form and rarely seen height of more than 20 feet in cultivation, Acer palmatum is a sight to behold. Its habit is rounded, often wider than it is tall, making it a beautiful addition to any landscape. The branchlets are glabrous, adding to the tree’s elegance.

The leaves of Acer palmatum are palmately five- or seven-lobed, ranging from 2 to 3.5 inches long and wide. These lobes are ovate-lanceolate, cleft two-thirds of the way to the base of the blade, and sharply double-toothed. The leaves start off green but transform into stunning shades of bronze or purplish in the autumn.

A Journey from Japan

Native to Japan, Acer palmatum was introduced to England in 1820. It is also found in China and Korea. The Japanese have cultivated this tree for centuries, resulting in an incredible variety of forms with different leaf colors and shapes. Botanists have given many of these forms intricate Latin names and meticulously classified them. However, in this article, we will focus on the cultivars that are most well-known and widely available today.

Exploring the Cultivars

Palmatum Group

The Palmatum Group consists of cultivars with foliage of normal shape, regardless of the size or number of lobes. This group includes the cultivars usually classified under var. heptalobum (septemlobum), which are characterized by large, seven-lobed leaves. One exception is ‘Elegans,’ which has foliage resembling both the Palmatum Group and the Dissectum Group.

The purple- and bronze-leaved cultivars in this group require full light to develop their vibrant coloring. However, they should be protected from the strongest sun to prevent color loss during hot summers. Some notable cultivars in this group are ‘Akegarasu,’ ‘Atropurpureum,’ ‘Bloodgood,’ ‘Fireglow,’ ‘Moonfire,’ ‘Murogawa,’ ‘Nuresagi,’ ‘Shojo,’ and ‘Umegae.’

Elegans Group

The Elegans Group features leaves that are mostly seven-lobed and divided to the base or near it. These leaves have lanceolate lobes, which are toothed or somewhat incised. The cultivars in this group are known for their erect habit and are distinct from the Dissectum Group. Some noteworthy cultivars in this group are ‘Beni Kagami,’ ‘Burgundy Lace,’ ‘Chitoseyama,’ ‘Elegans,’ ‘Hessei,’ ‘Katsura,’ ‘Kinran,’ ‘Nicholsonii,’ ‘Omurayama,’ ‘Rufescens,’ ‘Shinonome,’ ‘Sumingashi,’ ‘Trompenburg,’ and ‘Seiryu.’

Dissectum Group

The Dissectum Group is known for its heavily dissected leaves. Leaves in this group are deep red, bronzing in summer and turning red and orange in autumn. Cultivars in this group include ‘Crimson Queen,’ ‘Dissectum Atropurpureum,’ ‘Dissectum Flavescens,’ ‘Dissectum Roseomarginatum,’ ‘Dissectum Variegatum,’ ‘Filigree,’ ‘Garnet,’ ‘Ornatum,’ and ‘Seiryu.’

Linearilobum Group

The Linearilobum Group showcases leaves divided almost to the base into five or seven narrow lobes, which are finely toothed but not cut. Cultivars in this group include ‘Crippsii,’ ‘Linearilobum Atropurpureum,’ ‘Red Pygmy,’ and ‘Villa Taranto.’

Variegated Cultivars

Variegated cultivars add a touch of uniqueness to any garden. Some standout varieties in this group are ‘Butterfly,’ ‘Higasayama,’ ‘Kagero,’ ‘Kagiri Nishiki,’ ‘Orido Nishiki,’ ‘Shigitatsu Sawa,’ ‘Ukigumo,’ and ‘Versicolor.’

Miscellaneous Cultivars

Lastly, we have a few miscellaneous cultivars that deserve mention. These include ‘Hagoromo,’ ‘Okushimo’ (Crispum),’ and ‘Shishigashira’ (Ribesifolium).

Unraveling the Variations

Acer palmatum is a beloved species that has fascinated gardeners and botanists alike. To help you navigate the variations within this species, here is a breakdown of the three recognized subspecies:

  1. Acer palmatum subsp. matsumurae Koidz.: This subspecies features leaves with seven to nine lobes, divided more than three-quarters to the base. The margins are coarsely toothed.

  2. Acer palmatum subsp. amoenum (Carrière) Hara: Trees or shrubs in this subspecies can reach heights of up to 10 meters. The leaves have five to seven lobes and are divided up to two-thirds to the base. The margins are very finely serrated.

  3. Acer palmatum subsp. palmatum: Similar to subsp. amoenum, trees or shrubs in this subspecies can reach heights of up to 10 meters. However, they are usually wider than they are tall. The leaves have five to seven lobes and are divided two-thirds to three-quarters to the base. The margins are coarsely double-serrated.

Please note that wild-collected material of any of these subspecies is rare in cultivation.

Conclusion

Acer palmatum Thunb., the Smooth Japanese Maple, offers a wide array of cultivars that will captivate any gardener. From the Palmatum and Elegans Groups to the Dissectum, Linearilobum, and Variegated Cultivars, each selection has its own unique beauty. Whether you’re looking for a tree with vibrant purple leaves or one with finely dissected foliage, there is a cultivar that suits your taste.

At Tips Tree Planting, we have a passion for sharing our knowledge and expertise with fellow gardening enthusiasts. We hope this article has provided you with valuable insights into the captivating world of Acer palmatum Thunb. If you’re interested in learning more about trees and gardening, be sure to visit our website Tips Tree Planting.

Happy gardening, and may your garden be filled with the beauty of Acer palmatum Thunb.